The best stones to use are lava rocks. You can get like a 6 lbs bag from lowes for $10 or so. It's in the gril section. These rocks have holes in them which allows for more space for bacteria to grow. Take some of the lava rock and break it up and put a layer on the bottom of the tank. Be sure to rinse the lava rock off it has a lot of dust. Another good thing is to add some live plants to the tank. This will help with oxygen and removing waste that fish put off. Adding a few fish to a new tank is a good way to cycle faster. I've had a 60 gal fish tank with like 40 fish (like 5 different kinds) and only cleaned the tank once in 2 years. All I do is add water when needed.